Found in the Cathedral of the Deep. The player must first join Rosaria's Fingers and offer at least one Pale Tongue to rank up in the covenant. The player must then talk to Ringfinger Leonhard, who will appear at the entrance of Rosaria's Bed Chamber.
Once the player reaches Anor Londo and defeats Aldrich, Devourer of Gods, the orb can be found on the now-dead body of Rosaria. In some cases, Rosaria will die and leave the orb after Yhorm the Giant has been defeated.
Used to invade Leonhard in the room above the Aldrich, Devourer of Gods bonfire (Gwynevere's chamber in Dark Souls). Upon defeating him in his world, the player will obtain the Soul of Rosaria, the Crescent Moon Sword and his Silver Mask.